Is there a flaw in how New Jersey coastal communities are constructing new dune systems?

by Marsha Samuel and Kim Kosko, New Jersey Sea Grant Consortium

Dunes don’t particularly get much attention during your average day at the beach. While most beachgoers spend time sunning themselves on flat expanses of sand, or cooling down nearer the water’s edge, dunes aren’t exactly the star attraction for a visitor on the shore. But for close to a decade Dr. Michael Peek, associate professor of biology at William Paterson University and researcher for the New Jersey Sea Grant Consortium has made dunes his focus. Peek has logged countless hours on the beaches of New Jersey in his research focusing on Ammophilia breviligulata (American beachgrass), the glue that holds much of New Jersey’s dune systems together.

Why all the bother about this specific beachgrass? Ammophilia has been used almost exclusively as a dune builder on the New Jersey coast.  Dunes are dynamic entities. They accrete and deplete; they move and shift with changes in weather patterns; get damaged in coastal storms, and suffer through anthropegnic abuse. Dunes aren’t merely decorative elements in the landscape of the shore.  And in New Jersey with million dollar homes and businesses stretching almost end to end down the shore; dunes are the last line of defense against coastal hazards during extreme weather events like Hurricane Sandy and nor’easters. In effect, New Jersey’s dunes are a potential multi-billion dollar insurance policy.

Ammophilia plays a critical role in the protective process. When dynamic dunes deplete naturally, they can leave once-protected sections of the shore exposed to coastal flooding. In an attempt to mitigate the damage to dunes, coastal communities often plan Ammophilia seedlings to deliberately construct dune systems to act like barriers against coastal damage during storms, effectually shoring up the coast. However, there’s a fatal flaw in this approach. Communities often use only a single genotype of Ammophilia to build these dunes. This single genotype, called a monoculture, means that the young plants spread across the burgeoning dune system are genetically identical. In a perfect world, as long as the plants remain healthy and escape the effects of undue biological stresses, the whole system is likely to survive. This perfect storm of ideal conditions is almost never the case.  The genetic similarities are a danger to the formation of healthy dunes—if a disease to which the monoculture is susceptible infects the dune systems, it will in all likelihood wipe out the entire plant population.

Dr. Peek’s research focuses on understanding how these genetically identical plant populations perform within the dune environment. He’s examining not only the single most popular ecotype of American beachgrass called the “Cape” variety; he’s also comparing its performance against other genotypes within the Ammophilia family. In the laboratory, test plants are subjected to the same biotic stresses they’d encounter in the wild: extreme changes in climate, nutrient and moisture deprivation, and dealing with disease infiltration. The objective is to determine whether a more diverse population of Ammophilia would perform better than monocultures have in the past. In effect, he’s not just building a better beach grass—he’s building better dunes.

Another productive collaboration that’s occurred as part of this project have been Dr. Peek’s partnership with the Education staff at the NJSGC to train its field educators to evaluate and understand the health and performance of beachgrass populations in New Jersey.  He’s  also worked closely with them to develop lessons plans for use by teachers in New Jersey schools, bringing real-time research findings into the classroom.